Electronic equipment, such as televisions, telephones, radios, and computers, are often constructed using semiconductor components, such as integrated circuits and microprocessors. In an effort to ramp microprocessor speed semiconductor component manufacturers have become increasingly concerned with the RC time delay of interconnects. Some of the most publicized changes involve changes from aluminum to copper interconnects, but this alone does not meet speed requirements. A more effective approach is to simultaneously reduce line resistance and line capacitance. This is accomplished through the introduction of low-k dielectric materials (i.e., dielectric materials having a low dielectric constant and a high resistance) to take the place of high-k silica dielectrics. In addition, the associated etch stop and barrier layers, used to both protect the copper from exposure during processing and to provide an etch stop layer for the via etches, may also be switched from high dielectric to low dielectric materials. For example, the industry has been moving from silicon nitride etch stop layers to silicon carbide etch stop layers.
Because of the recent use of these low-k dielectric materials, the etching of the vias must be performed with great care. Accordingly, the etch stop layer may be etched all the way down to the underlying copper layer before the etch process is finished. This may result in some of the copper diffusing into the low-k dielectric layer leading to shorts in the interconnect layers, which may be devastating to the microprocessor.